Is WHEN you eat as important as WHAT you eat?

What we eat has a huge effect on our body and health. However, this is not the only factor that matters. A new study shows that having the right schedule for eating meals is the solution to fighting obesity.

Even though you may eat a healthy diet, research revealed that it defeats its purpose if you eat too close to bedtime, cram all your meals together, or wait too long between eating. This all depends on our body’s metabolism, which is affected by our circadian rhythm or “body clock.” Some may have the standard night-day body clock, while some may have different schedules, especially those who work on night shift or work both day and night, and it is not necessarily straightforward. (Related: Anyone Can Prepare Healthy Food with These Meal Prep Hacks.)

Researchers at Brigham and Women’s Hospital (BWH) conducted the first study showing how meal times affect the way you gain weight, depending on when you wake up and sleep. The study was published in The American Journal of Clinical Nutrition. The timing of meals has been studied in real world settings, in relation to melatonin onset — which marks the onset of sleep.

They examined body fat, body mass index (BMI), and the timing of food consumption. Then, they compared these with the time of day and the person’s body clock. The data was collected from 110 college-aged participants who were enrolled in a 30-day observational study to document sleep times and daily meal intake using a mobile phone app to time-stamp, document, and record the participants’ food intake over seven consecutive days of their regular routines.

In one of the nights during the 30-day study, participants were studied at the BWH Center for Clinical Investigation to assess the timing of their melatonin onset, marking onset of sleep, and their body composition.

“We found that the timing of food intake relative to melatonin onset, a marker of a person’s biological night, is associated with higher percent body fat and body mass index, and not associated with the time of day, amount or composition of food intake,” said Andrew W. McHill, lead author of the study and a researcher with the Division of Sleep and Circadian.

The findings suggest that the timing of when calories are consumed, relative to your own biological timing, may be more important for health than the actual time of day.

The study revealed that individuals with high body fat percentages consumed most of their calories shortly before going to sleep when melatonin levels were high, while those with lower percentages of body fat tended to go to bed a few hours after their last meal.

However, no relationship was detected between the clock hour of food intake, caloric amount, meal consumption, activity or exercise level, or sleep duration, and either of these body composition measures.

Researchers noted that the population of college-aged individuals may not represent the entire population in terms of food choices and body clock.

Still, the findings provided evidence that food consumption during the circadian evening plays an important role in body composition.

A 2010 study showed that snacking at night is associated with poor dietary quality and that skipping meals and snacking instead had affected the eating patterns and lifestyle of older adolescents.

In the same article, a 2013 study evaluated the role of food-timing in a weight-loss effectiveness program among 252 women and 258 men with BMIs above 31.4 and followed a 20-week weight loss treatment. The results revealed that late-lunch eaters lost weight at a slower rate, even though both groups had the same calories, diet, physical activity, and amount of sleep.

At the end of the day, it all boils down to discipline and balance. Eat your healthy meals at the right time. Wait a few hours after your last meal before going to bed.